Screen printing apparatus



Dec. 7, 1965 F. WEISS 3,221,649

SCREEN PRINTING APPARATUS Filed April 15, 1963 5 Sheets-Sheet 1 a 2 37 3/ 2a 32 4o 35 28 32 4/ A? 42 22 'l 9 I INVENTOR. FRANZ. Wass EH-F E.

5 Sheets-Sheet 2 Filed April 15, 1963 INVENTOR. FRANZ Wmss BY w; CLAW- PIE- Dec. 7, 1965 F. WEISS 3,221,649

SCREEN PRINTING APPARATUS Filed April 15, 1963 5 Sheets-Sheet 5 INVENTOR.

FRANZ W ass .BY z wmm liiL/ United States Patent 3,221,649 SCREEN PRINTING APPARATUS Franz Weiss, Park Ridge, 111., assignor to Poster Products, Inc., Chicago, IlL, a corporation of Illinois Filed Apr. 15, 1963, Ser. No. 272,995 4 Claims. (Cl. 101-126) This invention relates to a printing apparatus and process and more particularly to a printing apparatus and process which is particularly well adapted for multicolor printing.

A primary object of the present invention is to provide novel printing apparatus and process capable of producing multi-color prints in a novel and expeditous manner.

Printing apparatus capable of producing multi-color printing have been heretofore known in the art. However, such apparatus as have been heretofore known have commonly had several inherent disadvantages such as, for example, requiring an excessive amount of manual labor in the use thereof; being slow in operation; being large and cumbersome in size; being complicated in construction and operation; or being unreliable or inefficient in operation, or the like. It is an important object of the present invention to overcome such disadvantages.

Another object of the present invention is to afford a novel printing apparatuswand process which may be readily adapted for automatic operation.

Yet another object of the present invention is to afford a novel process and apparatus of the aforementioned type capable of producing high quality prints in a novel and expeditious manner.

A further object is to afford novel apparatus of the aforementioned type which is capable of relatively rapid operation.

Another object is to afford a novel process and apparatus wherein the apparatus involved is practical and efficient in commercial operation, and may be readily and economically produced commercially.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principles thereof and what I now consider to be the best mode in which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a top plan view of an apparatus embodying the principles of the present invention, with certain parts broken away;

FIG. 2 is a fragmentary sectional view taken substantially along the line 22 in FIG. '1;

FIG. 3 isa sectional view taken substantially along the line 3-3 in FIG. 1;

FIG. 4 is an enlarged, fragmentary sectional view taken substantially along the lines 44 in FIG. 1;

FIG. 5 is a fragmentary sectional view taken substantially along the line 5-5 in FIG. 3;

FIG. 6 is a fragmentary sectional view of a portion of the apparatus shown in FIG. 5, with certain parts disposed in different position; and

FIG. 7 is a wiring diagram for a portion of the mechanism embodied in the apparatus shown in FIG. 1.

A printing apparatus 1, embodying the principles of the present invention, is shown in the drawings to illustrate the preferred embodiment of the present invention. It is of the type particularly well adapted for carrying out 3,221,649 Patented Dec. 7, 1965 printing processes of the type commonly known in the trade as silk screen printing processes.

The apparatus 1 includes a supporting base 2, which includes two substantially parallel spaced upright supporting members 3 and 4 having bearings 5 and 6 mounted in the respective upper end portions thereof, FIG. 3. A shaft 7 is journaled in the bearings 5 and 6 and extends between, and outwardly through the sup porting members 3 and 4. Two gears 8 and 9 are mounted on the end portions of the shaft 7, which project outwardly from the supporting members 3 and 4, respectively. The gears 8 and 9 are secured to the shaft 7 for rotation therewith, in substantially upright, parallel spaced relation to each other. As will be discussed in greater detail presently, during the operation of the apparatus 1, the shaft 7 and the gears 8 and 9 are oscillated through a portion of a revolution. Such oscillation may be effected by any suitable means such as, for example, a suitable reversible motor, or clutch, not shown, operatively connected to the shaft 7.

The base 2 also includes additional supporting means in the form of a table 12, including an elongated, substantially rectangular-shaped table top 13 disposed vertically above 'the shaft 7 in horizontally extending, substantially parallel relation thereto. The table top 13 is supported in such position by suitable legs 14, FIG. 3.

A supporting member 15, in .the form of a segment of a cylinder, is mounted on and secured to the shaft 7 for rotation therewith, for a purpose which will be discussed in greater detail presently. The supporting member 15 includes an elongated supporting panel 16, which is substantially arcuate-shaped in transverse cross-section, FIGS. 3, 5, and 6. The supporting panel 16 is preferably made of aluminum, but may be made of any suitable material such as, for example, a suitable plastic.

ing member 15 is secured to the shaft 7 in such position that oscillation of the shaft 7 during operation of the apparatus 1 is effective to oscillate the supporting member 15 over the shaft 7 between the position shown in broken lines in FIG. 6 and the position shown in broken lines in FIG. 5.

The apparatus 1 includes a substantially rectangular shaped supporting frame 19, which includes two parallel end walls 20 and 21, and two substantially parallel side walls 22 and 23, which may be made of suitable material such as, for example, angle iron or the like. The supporting frame 19 is slidably supported for horizontal reciprocation above the gears 8 and 9 by suitable supporting means such as two guide walls 24 and 25 projecting upwardly from the base 2 in substantially parallel spaced relation to each other, outwardly of the gears 8 and 9, respectively, FIG. 3. Two elongated racks 26 and 27 are mounted on the bottom faces of the end walls 20 and 21, respectively, of the supporting frame 19 in operative meshing engagement with the upper portions of the gears 8 and 9, respectively. It will be seen that with this construction, oscillation of the gears 8 and 9, during operation of the apparatus 1, is effective to correspondingly reciprocate the supporting frame 19 horizontally along the guide walls 24 and 25 in a horizontal plane disposed above the table 12.

A substantially rectangular-shaped stencil screen frame 28, including two parallel end walls 29 and 30 and two substantially parallel side walls 31 and 32 is mounted on, and supported by the supporting frame 19, FIGS. 1, 3, and 5. A stencil screen 33 is secured to the stencil frame 28 at the edges thereof and is stretched thereacross, FIGS. 3 and 5. The stencil or printing pattern is applied to the underside of the screen 33 to produce certain areas 34 which are impervious and other areas 35 which are pervious. Color composition 36, which is to be applied to the article being printed in the operation of the apparatus 1, is placed over the pervious portions of the stencil screen 33. This coloring composition can be any well-known heavy concentrated, non-flowing printing ink which is sufficiently viscous to remain on top of the stencil screen under normal atmospheric conditions but which will flow through the openings in the pervious portions of the stencil screen when the pressure on the opposite side of the stencil screen is reduced.

The stencil screen frame 28 is pivotally secured to the supporting frame 19 by suitable hinges 37 attached to the side rail 22 of the supporting frame 19 and the side rail 31 of the stencil frame 33, FIGS. 1 and 5. A bracket 38 projects outwardly from the longitudinal central portion of the side rail 23 of the supporting frame 19, FIGS. 1 and 5, and a spring-urged solenoid 39, including a plunger 40, is mounted on the bracket 38 with the plunger 40 extending upwardly therethrough. A tongue 41 projects outwardly from the side rail 32 of the stencil screen frame 28 above the bracket 38, and has an elongated slot 42 opening outwardly through the outer end thereof. The plunger 40 of the solenoid 39 extends upwardly through the slot 42, and suitable abutment members, such as, for example, nuts 43 are mounted on the upper end portion of the plunger 40 in loosely overlying and underlying relation to the tongue 41. The plunger 40 of the sole noid 39 is spring-urged downwardly, so that when the solenoid 39 is deenergized, the plunger 40 and upper nut 43 are effective to yieldingly hold the stencil screen frame 28 in full downward position shown in solid lines in FIG. 5. When the solenoid 39 is energized, the plunger 40 is moved upwardly to thereby press the lower nut 43 upwardly against the tongue 41 and swing the stencil screen frame 28 upwardly around the hinges 37 into raised position, as shown in broken lines in FIG. 5. The supporting frame 19 is so disposed relative to the supporting member 15, that when the stencil screen frame 28 is disposed in the aforementioned lowered position, the stencil screen 33 rests on top of the supporting panel 16 and is bowed somewhat upwardly thereby. The movement of the plunger 40 between extended and retracted position is of sufiicient magnitude that when it is in extended position, it is effective to hold the stencil screen frame 28 in sufficiently elevated position to insure that the stencil screen 33 is disposed in upwardly spaced relation to the supporting member 15.

The supporting panel 16 is provided with a plurality of relatively closely spaced small holes 44, FIGS. 1, 3, and 5, over the entire surface thereof. An elongated, substantially rectangular-shaped, open-topped, vacuum housing 45, having a bottom wall 46, two substantially parallel upright end walls 47 and 48, and two substantially parallel upright side walls 49 and 50, FIGS. 4 and 6, is disposed below the supporting panel 16 with the upper edges of the walls 47-50 disposed in abutting engagement with the lower surface of the supporting panel 16. The vacuum housing is yieldingly supported in such position by an adjustable supporting unit 51, FIGS. 5 and 6, which includes a bottom plate 52 mounted on and secured to a plurality of adjusting screws 53 threaded through the table top 13 of the table 12. The supporting unit 51 includes a top plate 54 yieldingly supported on the bottom plate 52 by suitable means such as springs 55, FIG. 4, and the vacuum housing 45 is mounted on and supported by the top plate 54. The supporting unit 51 is supported by the adjusting screws 53 on the table top 13 in such position that the springs 55 are effective to yieldingly urge the vacuum housing 45 into the aforementioned abut ting relation to the under surface of the supporting panel 16.

An opening 56 extends through the longitudinal center portion of the bottom wall 46 of the vacuum housing 45, and one end of a suitable conduit, such as a pipe or hose 57 is connected to the opening 56. The other end of the hose 57 is connected to a suitable source of vacuum such as, for example, a vacuum tank 58 which may be evacuated, as required, by suitable means such as, for example, a suitable vacuum pump, not shown, connected thereto by a suitable conduit, such as a pipe or hose 59.

Suitable paperholding means, such as paper clamps 60 of a type well known in the art, are mounted on the leading edge 61 of the supporting panel 16, and in the operation of the apparatus 1, at the start of a cycle of operation, the supporting member 15 is disposed in the position shown in broken lines in FIG. 6, in which position, the sheet material to be imprinted, such as a sheet 62, may be fed onto the top of the supporting panel 16 from the right, as viewed in FIG. 6, into such position that the leading edge of the sheet 62 is firmly clamped by the clamping member 60. The sheets to be printed, such as the sheet 62, may be made of any suitable type of porous sheet material, such as, for example, an eighty pound sized paper. In general, it is preferable not to use clayfilled papers or other papers which are adversely affected by the application of a solvent. Prior to feeding the sheet material through the apparatus 1, a liquid which is at least a partial solvent for the coloring material, such as, for example, naphtha, mineral spirits, xylene, toluene or benzene, preferably is applied to the upper surface of the porous sheet material 62 by means of a brush, sponge, spray, or in any other suitable manner.

In the operation of the apparatus 1, a cycle of operation begins with the supporting member 15 and the stencil screen 33 disposed in the position shown in broken lines in FIG. 6. A sheet of the porous sheet material 62 may then be fed from any suitable source of supply such as, for example, a feed table 63, FIG. 5, into the aforementioned position on the supporting panel 16, wherein the leading edge of the sheet 62 is disposed under the clamping member 60. Thereafter, the shaft 7, and, therefore, the gears 8 and 9 and the supporting member 15 rotate in a counterclockwise direction, to thereby move the stencil screen 33 to the left. At the same time, the rotation of the supporting member 15 is effective to move the sheet 62 engaged by the clamping member 60 along an arcuate path to the left. The sheet 62 is firmly clamped between the supporting panel 16 and the stencil 33, during the movement thereof over the vacuum housing 45. As the sheet 62 moves over the housing 45 the reduced pressure in the housing 45 applies suction through the holes 44 to the sheet 62 to thereby remove any excess liquid from the sheet. Also, the reduced pressure in the housing 45 causes the coloring composition or printing ink on the remote side of the stencil screen 33 to be pulled through the openings in the pervious portions of the stencil screen 33 onto the porous sheet 62, as those portions pass over the housing 45. Preferably, a vacuum of from twenty to twenty-eight inches of mercury is maintained in the housing 45. The printing colors which are placed on top of the stencil screen 33 over the pervious portions can, if desired, be enclosed in a boundary wall made of rubber, metal, or other suitable material, in order to confine them to a predetermined area. This is not always necessary.

The arch of the supporting panel 16 is of the same length as the printing surface of the stencil screen 33, and the gears 8 and 9, the racks 26 and 27, and the supporting member 15 are so constituted and arranged relative to each other that as the supporting member 15 swings in a full path of movement in a counterclockwise direction from its initial position shown in broken liiie in FIG. 6, the stencil screen 33 is correspondingly moved from right to left, as viewed in FIG. 6, so that the entire length of the printing surface of the stencil screen 33, and the corresponding portions of the supporting panel 16 are moved from right to left across the open upper face of the vacuum housing 45 to thereby progressively print the sheet 62 being correspondingly fed across the vacuum housing 45 from right to left, as viewed in FIG. 6.

At the end of the printing stroke of the supporting member and the stencil screen 33, the pirnted sheet 62 may be lifted from the outer surface of the supporting panel 16 either manually, or by suitable automatic pick-off devices, not shown. It will be understood by those skilled in the art that after the sheet being printed has passed the housing 45, it is not necessary for the purposes of this invention that the sheet remain on the outer face of the supporting surface 16, but, if desired, it may be fed therefrom by any suitable pick-off mechanism well known in the art, such as a pick-off mechanism indicated generally at 64 in FIG. 5. At the end of the aforementioned printing stroke of the supporting member 15, the trailing edge 65 thereof and the right side of the stencil frame 28 has moved to the position shown in broken lines in FIG. 5, wherein the trailing edge of the sheet 62 which has just been printed is no longer clamped between the screen 33 and the panel 15.

At that time, a switch 66, FIG. 7, may be closed manually, or by suitable automatic mechanism, not shown, to thereby energize the solenoid 39 and cause the stencil screen frame 28 to pivot upwardly in a counterclockwise direction, as viewed in FIG. 5, into the elevated position shown in broken lines in FIG. 5. The circuit for such energization of the solenoid 39 may run from one side 67 of a suitable source of electric power, such as, for example, a suitable wall plug, not shown, through a conductor 68, the closed switch 66, a conductor 69, the windings of the solenoid 49, and a conductor 70 back to the other side 71 of the source of power, FIG. 7.

With the stencil screen frame 28 disposed in the aforementioned elevated position, the supporting member 15 may be oscillated in a clockwise direction, as viewed in FIGS. 5 and 6, back to its initial starting position shown in broken lines in FIG. 6, without the stencil screen 33 being in contact with the supporting member 16, and with'the stencil screen 33 disposed above the supporting member 16 a suificient distance that the suction in the housing 45 is ineffective to draw coloring material through the screen 33 during the reverse stroke of the supporting member 15 and the stencil screen 33 back to their original position. Such reversal of the supporting member 15 and the stencil screen 33 may be effected by any suitable means, such as, for example, any suitable reversing switch 66 readily available on the market, shown in FIG. 3 mounted in position'to be actuated by the shaft 7, and effective, in a well-known manner, to reverse the operation of a suitable drive mechanism, such as, for example, a reversible motor, not shown.

From the foregoing, it will be seen that in the operation of the novel apparatus 1, and in carrying out the process of the present invention, a stencil screen frame 28 embodying a stencil screen 33, which has coloring material 34 disposed at the proper places thereon, may be mounted on the supporting frame 19, with the supporting member 15 and the stencil screen 33 disposed in the position shown in broken lines in FIG. 6. Thereafter, a sheet of material to be printed may be fed from the right to the left onto the supporting panel 16 into position wherein the leading edge of the sheet material is clampingly engaged by the clamping means 60. Thereafter, the supporting member 15 may be rotated in a counterclockwise direction through a complete printing stroke, the supporting frame 19 being correspondingly moved from right to left through a complete printing stroke, to thereby sequentially print the adjacent stencil pattern upon the underlying corresponding portions of the sheet 62 as they move across the housing 45 with the panel 16, the printing on the sheet being applied progressively from left to right, as viewed in FIGS. 5 and 6.

Thereafter, the printed sheet may be removed from the supporting panel 16, the solenoid 39 may be energized to raise the printing screen 33 into the elevated position shown in broken lines in FIG. 5, and the supporting member 15 may be rotated back to its starting position, the rotation of the gears 8 and 9 being effective through their engagement with the racks 26 and 27 to correspondingly move the supporting frame 19 back to its starting position. Thereafter, the switch 66 may be opened to thereby deenergize the solenoid 39 and again move the printing frame 28 downwardly into closed position, as shown in solid lines in FIG. 5, and the apparatus 1 is then in condition to start a new cycle of operation.

From the foregoing it will be seen that the present invention affords novel apparatus of the aforementioned type which is practical and eflicient in operation, and may be readily and economically produced commercially.

Thus, while I have illustrated and described the preferred embodiment of my invention, it is to be understood that this is capable of variation and modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. A printing apparatus for printing on a sheet of porous material comprising (a) a substantially horizontally extending stencil screen having pervious portions,

(b) a coloring composition on the top of said pervious portions,

(c) means for substantially horizontally reciprocating said screen through (1) a printing stroke and (2) a return stroke,

(d) a perforated, arcuate-shaped supporting panel disposed beneath said screen,

(e) means for oscillating said panel around the radius of the arch thereof through (1) a printing stroke (a') during movement of said screen through said first-mentioned printing stroke (b') in the same general direction as the movement of said screen, and (c') in position to progressively press such a sheet against the lower side of said screen, and (2) a return stroke (a') during movement of said screen through said first-mentioned return stroke, and (b') in the same general direction as the movement of said screen,

(f) means for holding said screen in upwardly spaced relation to said panel during said return stroke, and

(g) means for applying reduced pressure to the bottom of said panel and thereby to the side of said sheet remote from said screen during said printing stroke,

(h) said last-named means being i (1) the sole pressure means for causing said coloring composition to be deposited on said porous sheet, and

(2) disposed in position to apply said reduced pressure at any one time to only a small fraction of the arch, of said panel.

2. A printing apparatus for printing on a sheet of porous material comprising (a) a substantially horizontally extending stencil screen having pervious portions,

(b) a coloring composition on the top of said pervious portions,

(0) means for substantially horizontally reciprocating said screen through (1) a printing stroke and (2) a return stroke,

(d) a perforated, arcuate-shapcd supporting panel disposed beneath said screen,

(e) means for oscillating said panel around the radius of the arch thereof through (1) a printing stroke (a) during movement of said screen through said first-mentioned printing stroke (b) in the same general direction as the movement of said screen, and (c') in position to progressively press such a sheet against the lower side of said screen, and (2) a return stroke (a) during movement of said screen through said first-mentioned return stroke, and (b) in the same general direction as the movement of said screen,

(f) means for holding said screen in upwardly spaced relation to said panel during said return stroke, and

(g) means for applying reduced pressure to the bottom of said panel and thereby to the side of said sheet remote from said screen during said printing stroke,

(h) said last-named means (1) being the sole pressure means for causing said coloring composition to be deposited on said porous sheet,

(2) comprising an elongated housing (a) having an open top and (b) disposed (1') substantially vertically above the axis of rotation of said panel (2') in substantially parallel relation thereto, and (3') with said open top disposed against the lower face of said panel in substantially sealed relation thereto, and

(3) comprising means for reducing the pressure in said housing,

(i) the width of said housing, chordal to the arch of said panel, being a small fraction of the entire printing stroke of said screen, and

(j) said housing being disposed in position to so engage said panel at a portion of said panel whereat said panel is so pressed against said heat during said printing stroke. 3. Printing apparatus as defined in claim 2, and in which (a) said means for reciprocating said screen includes (1) two gears operatively connected to said panel for oscillation therewith, and (2) two elongated racks (a) operatively connected to said screen in supporting relation thereto, and (b) operatively engaged with said gears for reciprocation thereby during said oscillation of said panel. 4. Printing apparatus as defined in claim 3, and in which (a) said means for holding said screen in upwardly spaced relation include (1) a supporting frame (a) mounted on said racks for movement therewith, and (b) operatively connected to said screen in supporting relation thereto, (b) said screen is pivotally connected to said frame,

and (c) said last-mentioned means includes means mounted on said frame and operatively connected to said screen for pivoting said screen upwardly relative to said frame into said upwardly spaced position.

References Cited by the Examiner UNITED STATES PATENTS 1,546,834 7/1925 Harrington 101--129 1,742,249 1/1930 Hamlin 101126 2,419,694 4/ 1947 Shuttleworth et al. 10l-129 2,866,405 12/1958 Black 101-126 2,892,398 6/1959 Sutlilf 101-126 2,918,866 12/1959 Reed 101--126 3,078,792 2/1963 Kerstan 101-124 3,129,442 4/1964 Leckie 101126 X 3,137,230 6/1964 Ichinose 101123 X FOREIGN PATENTS 518,036 2/1940 Great Britain.

DAVID KLEIN, Primary Examiner.

WILLIAM B. PENN, Examiner. 

1. A PRINTING APPARATUS FOR PRINTING ON A SHEET OF POROUS MATERIAL COMPRISING (A) A SUBSTANTIALLY HORIZONTALLY EXTENDING STENCIL SCREEN HAVING PERVIOUS PORTIONS, (B) A COLORING COMPOSITION ON THE TOP OF SAID PERVIOUS PORTIONS, (C) MEANS FOR SUBSTANTIALLY HORIZONTALLY RECIPROCATING SAID SCREEN THROUGH (1) A PRINTING STROKE AND (2) A RETURN STROKE, (D) A PERORATED, ARCUATE-SHAPED SUPPORTING PANEL DISPOSED BENEATH SAID SCREEN, (E) MEANS FOR OSCILLATING SAID PANEL AROUND THE RADIUS OF THE ARCH THEREOF THROUGH (1) A PRINTING STROKE (A'') DURING MOVEMENT OF SAID SCREEN THROUGH SAID FIRST-MENTIONED PRINTING STROKE (B'') IN THE SAME GENERAL DIRECTION AS THE MOVEMENT OF SAID SCREEN, AND (C'') IN POSITION TO PROGRESSIVELY PRESS SUCH A SHEET AGAINST THE LOWER SIDE OF SAID SCREEN, AND (2) A RETURN STROKE (A'') DURING MOVEMENT OF SAID SCREEN THROUGH SAID FIRST-MENTIONED RETURN STROKE, AND (B'') IN THE SAME GENERAL DIRECTION AS THE MOVEMENT OF SAID SCREEN, (F) MEANS FOR HOLDING SAID SCREEN IN UPWARDLY SPACED RELATION TO SAID PANEL DURING SAID RETURN STROKE, AND (G) MEANS FOR APPLYING REDUCED PRESSURE TO THE BOTTOM OF SAID PANEL AND THEREBY TO THE SIDE OF SAID SHEET REMOTE FROM SAID SCREEN DURING SAID PRINTING STROKE, (H) SAID LAST-NAMED MEANS BEING (1) THE SOLE PRESSURE MEANS FOR CAUSING SAID COLORING COMPOSITION TO BE DEPOSITED ON SAID POROUS SHEET, AND (2) DISPOSED IN POSITION TO APPLY SAID REDUCED PRESSURE AT ANY ONE TIME TO ONLY A SMALL FRACTION OF THE ARCH, OF SAID PANEL. 